Upgrade StorageiPad Library Sync Issues
I accidentally purged my zotero library data on my iPad application and now I can open any of the pdfs. I tried following the instructions in the pop up window with the error that the documents aren’t synced but it hasn’t fixed the issue. I can still open the pdfs on my laptop, it’s just my iPad that won’t work.
If the file is still available online, trying to open it on the iPad will download it again. If you can't open a file, it's not online — that's what the Files Not Syncing is explaining.
Note that you only upgraded your storage plan today, so you've previously been at your storage quota. That means that two things:
1) Any additional files added on your computer weren't being uploaded before, so you'd have to sync that computer before they became available elsewhere.
2) If you added files on the iPad, they might never have been uploaded before you removed them. In that case, you wouldn't be able to access them on your computer either. You'd have to download them again from the original site.